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filling a large commercial system 5 story

JackKram Member Posts: 1
We are in the beginning process of filling the hydronic heating system of a 5 story building. In order to hopefully speed up the task I have initiated the fill. My theory is to apply enough water pressure to to get the basement loop filled and possibly partially up into the risers of the 1st floor so we can check packing nuts on unit shut off valves.

My question is if the gauges on the boilers and pumps read 16 psig is the water column up @ 32 feet. (Theory: 1 psig raises water 2.30 feet.)? Or am I looking at head pressure of the column and the water is only up @7 feet? (Theory: 16 psig multiplied by .434 = @ 7 feet)



  • JohnNY
    JohnNY Member Posts: 2,657
    Your static height of water at 16psi is 36.96 feet. (16psi x 2.31).
    Contact John "JohnNY" Cataneo, Master Plumber
    in New York
    in New Jersey
    for Consulting Work
    or take his class.
  • hot_rod
    hot_rod Member Posts: 14,785
    If the goal is to fill and purge a large zone or loop, you need the fill pressure noted as well as sufficient flow. Or break the system to small zones or sections and purge one at a time.

    Similar to geo loop fields, installers that fill and purge the entire loop field use a high flow fill pump, like a high gpm pool pump or more. A 1/2" fill line will only supply so much flow.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • SWEI
    SWEI Member Posts: 7,356
    If you have isolation valves on the boiler(s) and expansion tank, you can crank up the system pressure (think 50+ PSI) which makes purging a lot easier.
  • hot_rod
    hot_rod Member Posts: 14,785
    Most of the manufacturers offer 3/4 fill valves. Sometimes referred to as commercial fill valves.

    This one will flow around 9 gpm, about twice the gpm of the 1/2" version.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Paul48
    Paul48 Member Posts: 4,470
    You might want to put a gauge on the top floor, then use the fill to pressurize the system. See if it holds pressure. If it's really bad, you might want to switch to compressed air. I'd rather chase an air leak than water.
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